1. Field of the Invention
The present invention relates to a recording/reproducing apparatus for performing recording/reproducing operations by inserting a cartridge containing a recording medium, such as a magnetic disk, into the apparatus, and, more particularly, to a door opening-and-closing mechanism for opening and closing an opening used for inserting a cartridge.
2. Description of the Related Art
A door opening-and-closing mechanism is widely used in, for example, a magnetic recording/reproducing apparatus for performing recording/reproducing operations of information on a magnetic disk contained in a disk cartridge. The door opening-and-closing mechanism prevents entry of foreign matter, such as dust, into the apparatus from an opening by a door provided at the opening for inserting a disk cartridge therein, when the disk cartridge is not loaded.
As disclosed, for example, in Japanese Unexamined Patent Publication No. 63-200386, in a conventionally known door opening-and-closing mechanism, a plate-shaped door is rotatably supported at the front face plate with an opening, and biased toward the closing direction of the opening by means of a torsion coil spring. In such a prior art door opening-and-closing mechanism, the opening is closed by the door, when the disk cartridge is not loaded. During insertion of the disk cartridge into the apparatus from the opening, the door is pushed by the disk cartridge and rotated, causing the disk cartridge to be loaded in position. Ejection of the disk cartridge out the apparatus causes rotation of the door in the opposite direction due to the biasing force of the torsion coil spring, whereby the door is re-closed.
The above-described conventional shutter opening-and-closing mechanism has the following problems. When the door is accidentally contacted by the operator with, for example, his finger or a writing material, the door is easily opened, allowing the entrance of foreign matter into the apparatus, since the door is biased in the closing direction of the opening merely by the torsion coil spring. In addition, in the game machine field or the like, disk cartridges of various sizes and shapes are sometimes used. In such a case, when the above-described conventional shutter opening-and-closing mechanism is used, the door is easily opened by disk cartridges which are not of the regular type, so that failure of the mechanism in the apparatus results due to accidental insertion of a disk cartridge which is not of the regular type.